American Scientist

As we age, the major arteries of our bodies frequently become thickened with plaque, a fatty material with an oatmeal-like consistency that builds up along the inner lining of blood vessels. The reason plaque forms isn’t entirely known, but it seems to be related to high levels of cholesterol inducing an inflammatory response, which can also attract and trap more cellular debris over time. The condition is called atherosclerosis, a combination of the Greek words for paste and hardness. As a plaque becomes more advanced, one of two problems can occur. The first and most common is narrowing of the inside of the artery, known as stenosis. When severe, blood supply to a body area such as the heart or leg is in jeopardy. The second problem occurs if the plaque ruptures. This event can cause outright blockage of the artery, cutting off blood flow entirely, or give rise to an embolus, a piece of debris released from the diseased artery wall. An embolus reduces blood supply once it travels downstream and abruptly blocks smaller arteries there.